A low-power monolithic GaAs FET bandpass filter based on negative resistance technique

This paper describes a monolithic GaAs FET active bandpass filter utilizing negative resistance elements. The negative resistance element was realized with a common-drain FET with series inductive feedback and the measured output impedance characteristics are given. The fabricated monolithic fourth-order filter showed an insertion loss of 0.7 dB at 4.85 GHz and a 3-dB bandwidth of 50 MHz with a DC power consumption of 7.5 mW.